The present invention concerns a system for controlling the regeneration of depollution means integrated in an exhaust line of a motor vehicle engine.
More particularly, the invention relates to such a system in which the engine is associated with common rail means for the supply of fuel to the cylinders thereof, according to at least one post-injection.
Such a post-injection is, in a standard manner, an injection of fuel after the high dead center of the cylinder under consideration.
These supply means are adapted to implement, at constant torque, through modification of parameters for controlling the operation of the engine, different regeneration strategies making it possible to obtain different thermal levels in the exhaust line.
Thus, for example, supply means implementing regeneration strategies called normal strategy, level 1 strategy, level 2 strategy and/or over-calibrated level 2 strategy, have already been proposed.
Indeed, it is known that, to ensure the regeneration of depollution means, such as a particle filter, the soot trapped therein are burned thanks to the thermal energy provided by the engine and to the exotherm obtained by the conversion of the HC and of the CO on means forming oxidation catalyst, placed, for example, upstream of the particle filter.
This combustion can be assisted by a catalyzing element, mixed with the soot, coming, for example, from a regeneration assistance additive, mixed with the fuel for the supply of the engine, or by a catalyst deposited directly on the walls of the particle filter (catalyzed particle filter).
The higher the thermal levels in the exhaust line at the inlet of the particle filter, the shorter the duration of the filter regeneration.
However, the use of post-injections generates a dilution of the lubrication oil of the engine by the fuel, which degrades the lubrication properties thereof, and translates in particular into a reduction of the viscosity which can lead, if this viscosity is too low, to engine breakage.